When I start comming down with a cold, I actively use a natural nose spray called Xlear (pronounced "clear"). It contains xylitol, a natural sweetener, that has proven effective at helping your membranes resist bacteria. It's all natural and safe for even infants. In fact, studies have shown that children that use xlear regularly have a decrease in ear infections. It doesn't have any immediate afrin-like effect but I use it many times a day and find it reduces my symptoms overall more quickly.
I also use a neti pot which allows you to rinse out your sinuses with a salt water mixture. It is particularly effective for allergies or for cleaning out your sinuses after working in a dusty area. If the neti pot is a little awkward for you, there's another version (I can't remember the name right now) that allows you to squeeze the solution into your nasal cavity rather than pouring it in. I'll post the name later when I find it.
Here are links to these products.
You can find a variety of neti pots at health food stores. This version is sold at Walgreens SinuCleanse - the first word in Sinus Relief - Home XlearINC: Quality Xylitol Products